所以，我猜想完成打字意味着你只是停下来一会儿，比如 5
秒。因此，考虑到这一点，让我们在用户释放一个键时启动一个计时器，并在他们按下一个键时清除它。我决定有问题的输入将是#myInput。

做几个假设…

//setup before functions
var typingTimer;                //timer identifier
var doneTypingInterval = 5000;  //time in ms, 5 seconds for example
var $input = $('#myInput');

//on keyup, start the countdown
$input.on('keyup', function () {
  clearTimeout(typingTimer);
  typingTimer = setTimeout(doneTyping, doneTypingInterval);
});

//on keydown, clear the countdown 
$input.on('keydown', function () {
  clearTimeout(typingTimer);
});

//user is "finished typing," do something
function doneTyping () {
  //do something
}